The proposed study addresses an under-researched, but likely important implication of sleep variations in a particular social and developmental context: It asks how mothers' sleep deficits arise and what they mean for parenting of toddlers. Toddlers create challenges for parents and many parents of toddlers experience sleep deficits, which could amplify the parenting challenges. The study will test a model in which (1) family stressors along with both family and mothers' individual resources influence (2) family chaos, in terms of fewer predictable routines and more noise, which in turn influences (3) mothers' sleep, in terms of extent, fragmentation, and variability, which influences (4) mothers' state levels of cognitive self-regulation, measured in structured tasks, which in turn influences (5) mothers' parenting of their toddlers. The study will also test a set of hypothesized mother temperament moderators of the paths from chaos to sleep (by trait negative affectivity), from sleep to self-regulation to parenting (by trait effortful control and by trait positive affectivity). The study will follow a sample of 250 mothers from toddler age 30 months to toddler age 36 months, and both continuity and predictors of change will be modeled. The sample will be recruited in two geographical areas and represent a range of socioeconomic levels and both European-American and African-American families. The study will advance knowledge about family environment and mother factors influencing mothers' sleep deficits, about how sleep deficits link to self-regulation and parenting, and about how mother temperament dimensions moderate the paths from environment to mother sleep and from mother sleep to self-regulation and parenting. Ultimately, the study will offer new targets for early childhood clinical and prevention research.